Core B is the tissue, cell and tissue culture core for the program project. This core has continuously served the requirements of all projects for the past 14 years of funding. The previous efforts of Core B were confined to supplyklg tissue, freshly dispersed cells and cultured cells and tissues to the various projects for morphological, functional and molecular analyses. An exciting new addition to this core for this funding cycle is cell surfing. Details of both the ongoing and new functions of the core are described in this section. Dr. Kathleen Keef will be responsible for the overall dkection of the core as she has done for the past 5 years. Dr. Tamas Ordog has now been added as a co-director of this core and he will be responsible for overseeing the cell sorting activities. Dr. Ordog has been the central figure in ithe development of techniques currently used here for the purification of ICC using cell sorting. During the previous fundinlg period work focused upon three different animal models (i.e., dog, mouse and guinea-pig). in this new application the major focus has shined to the mouse model since it has significant utility as a model of human motility and because of the enormous advantages engendered through access to knockout and transgenic mice. Whenever possible experiments will also be repeated using cells and tissues isolated from human colon obtained during surgeries for non-obstructive neoplasms and in some cases human jejunum obtained from gastric bypass surgeries. Dr. Keef has published studies using both of these human muscles. In summary, Core B is an essential element to achieving the goals set out in the 5 projects described in this program project.